Genital surgery is "less significant" to most transgender people if hormones effectively change their appearance and "they are happy with the way they look," said Spiegel.
When female-to-male patients do opt for surgery, like Bono, doctors start with the nerve-rich clitoris to begin build a penis -- and to preserve some sexual sensation.
"The male and female genital structure is basically homologous," said Dr. Loren Schechter, head of plastic surgery at Chicago Medical School at Rosalind Franklin University of Medicine and Science and the Chicago Gender Center.
He does scores of what he calls "gender confirmation" surgeries annually.
Male-to-female surgery is five times more common than the surgery that Bono says he would like to have.
"The reason is cost and a major factor is the risk of complications," said Schechter. "It's not ideal, and it's a difficult operation."
Phalloplasty can run as high as $50,000 to $75,000, while vagina reconstruction costs about $21,500. Only about a fifth of all patients have insurance plans that cover these procedures, he said.
Hormone treatments with testosterone make the clitoris grow, sometimes to an inch or two, so surgeons can simply lengthen it in metoidioplasty -- the least invasive procedure.
They release the restraining ligaments that hold the clitoris next to the public bone and give the patient enough of a penis to urinate while standing, but not to have intercourse.
"When doing gender confirmation surgery, people know who they are and the goal is to make the body congruous with the mind," said Schechter
Sexual performance is not always of concern. "Most want to just pass as a member of the opposite sex and not be hassled when they walk into a male bathroom," he said.
In addition to lengthening the clitoris, doctors can create a urinary tube through the micro-phallus by using portions of the labia and minor or the vagina.
The third and riskiest option involves "flaps" or transferring tissue from a distant part of the body such as the forearm or the back or thigh and inserting a penile prosthesis.
"The goal is to truly reconstruct a penis," he said.
Bono has said he has been in contact with a doctor from Belgrade in Serbia. There, according to Schechter, Dr. Rados Djinovic is an expert in reconstructive surgery.
"Europe has some outstanding surgeons," said Schechter, who has worked with Djinovic.
He said that his medical colleagues had coincidentally talked about Chaz Bono's decision in the operating room this week.
"It's all about education, and from a physical standpoint, helping people who need help," he said. "There shouldn't be a stigma associated with it ... This condition has been known throughout time and history and different cultures."
"We are trying to make people feel comfortable in their own body," said Schechter. "Not everyone wants it or is a candidate for it, but there's an entire spectrum of options open to them."